Method of producing practically pure iron.



critics.

ARTHUR P. scoTT, or BRACKENRIDGE, PENNSYLVANIA, ASSIGNOR To ALLEGHENYSTEEL COMPANY, OF PITTSBURGH, EENNSYLVANLA, A CORPORATION OF PENDLMETHOD OF PRODUCING PRACTICALLY PURE IRON.

SYLVANIA.

1 $44,256. Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that I, ARTHUR P. Soon, a subject of the King of GreatBritain, residing at Brackenridge, in the county of Allegheny and Stateof Pennsylvania, have 1nvented new and useful Improvements in Methods ofProducing Practically lure Iron, of which the following is aspec1fication.

This invention relates to an improved method of producing practicallypure iron.

In the manufacture of steel, and in the manufacture of ingot-iron asmade by the basic or acid open hearth process, the Bessemer or crucibleprocess, or the electric furnace process, when the metal is tapped fromthe furnace or vessel into the ladle previous to ouring or casting intoingots, substantial y all the slag accompanies it. Beinglighter than themetal this slag for the most part floats on the surface of the metal butsmall quantities of the slag are distributed through the body of themetal in the ladle, as globules or particles, being held by internalfriction of the slag against the steel. Ordinarily the molten iron ispromptly poured into the molds and these globules or particles of slagpass into the molds with the iron, and become entrapped in thesolidifying metal.

The resulting ingot therefore contains occluded in its mass, slag invarying quantities, to the great detriment of the finished material.

The object of the present invention is to so treat the metal bath as toremove these occluded slag particles or globules.

It is well known that the smaller a body is the greater is theproportionate friction surface presented by it, and that when aplurality of very small bodies are combined the friction surface isgreatly decreased, and I take advantage of this well known fact incarrying out the improved process. In practising my invention I meltdown and refine preferably in an open hearth furnace, or in an electricfurnace, or in any combination of the two, a charge of pig iron, castiron or iron in any other form or combination ordinarily' employed incharging such furnaces in the usual Way. The impurities usuallyencountered, such as carbon, manganese, phosphorus, silicon and sulfur,are oxidized and eliminated from the bath to the greatest Patented June22, i915.

Application filed October 6, 1910. Serial No. 585,718.

possible extent by the application of heat,v

fluxes and reagents according to well known practice. When the desiredpurity is ob tained the metal is tapped or poured from the furnace, orconverter, into the ladle, and it is allowed to remain tranquil for aperiod of four minutes or thereabout before teeming is commenced, duringwhich period the slag floats out. By thus allowing the metal in theladle to remain tranquil, gathering or coalescing of the slag particlesis permitted, whereby the friction surface is reduced and the gatheredor coalesced particles will float to the surface. If the teeming iscommenced without permitting the metal to stand as described, theoccluded slag particles would be held in the metal bath by friction andas a consequence would become entrapped in the solidif ing metal in themolds. If desired the fibating out or elimination of the slag globulesor particles, may be expedited during the period the metal is allowed tostand, by agitation of the metal in the ladle, either by rotating theladle, or otherwise, this step being analogous to the well knowngathering or coalescing of the fat globules in butter making.

By the foregoing process I am enabled to produce a practically pure ironwhich, because of its high degree of purity will solidify'without blowholes or spongy top, and with little or no piping. It is lesssusceptible to corrosion than any other known iron or steel; is highlymalleable and ductile; may be worked at a low heat; and by reason of thefineness of its surface it is particularly receptive to metal coatingsof any kind.

I claim as my invention 1. The process of producing practically pureiron which comprises melting down iron in combination with fluxes andreagents to separate the impurities, transferring the purified metal toa ladle and allowing it to remain in the latter for a period of fourminutes or thereabout, without heating and without the addition of slagproducing reagents, and finally teeming.

2. The process of producing practically pure iron comprising meltingdown iron in combination with the usual fluxes or reagents, tapping orpouring the metal into a ladle, and allowing it to remain in the ladleagents to purify the same, tapping or pouring the molten metal into aladle and allow ing the same to remain in the ladle for a period of fourminutes or thereabout, and concurrently agitating the molten metalbefore teeming.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

ARTHUR P. SCOTT.

Witnesses:

CHAS. E. RIORDAN, WM. S. Honors.

